Shervin,
I use the Focus Firestore 4 Pro 40GB (PAL version) which give me 3 hours footage. This is great when shooting shows and other long events, you dont need to plan for the right time to change tapes.

I like the Firestore even if there are some minor things:
Its shipped only with a belt-clip, a camera mount-kit is available as accessories.

The battery holds for only 90 min, which means that you have to switch power source before your disk is filled up. If you are indoors you can use the included power adapter connecting to the power system.

On the other hand the Firestore seems to be reliable and I have not experienced any drop-outs during my shooting.
Connecting to the computer is as easy as connecting a firewire-cable to the computer which automatically detects the Firestore. You can then export the footage direct into your NLE without any capture!

I would suggest that you still roll tape, in addition to using the DTE. Should anything bad happen, you'll have a tape back up and the tapes are good for archiving. Most of the folks I know who use DTE's, also shoot tape.

A good friend accidentally broke the bracket for his Firestor. Luckily, he was holding it. But had it tumbled and broken, he was would have been covered because he was also shooting tape.

During one of my first live shoot with the Firestore I discovered that I had forgotten to set "remote recording" in the meny of the Firestore.
Even if I had set DVcontrol to "on" on my XL-2 and everything seem to record, the red record-dot was on in the XL-2 viewfinder and also the display showed that the Firestore disk was running, nothing was recorded to the Firestore disk! The Firestore disk was set to manual recording (which is the default setting).